Preparation of crystalline poly



- to balsarnlike or soft resinouslike polymers.

r 3,159,613 PREPARATION 8F CRYSTALLH IE PWLYWENYL ALKYL ETHERS) Edwin J. Vandenberg, Wilmington,'i)el., assignor to Hercules Powder Company, Wilmington, Del, a corporation of Delaware No Drawing. Filed Dec. 27, 1960, Ser. No. 73,328

6 Claims. (Cl. sea-91.1

This invention relates to a new process for the production of 'poly(vinylethers) of high molecular weight and high crystallinity. I g

It is well known that vinyl ethers may be poly erized in bulk or solution with Friedel, Cratts catalysts to yield polymers that vary from viscous liquid Under certain conditions and using boron trifluoride etherates as catalysts it has been possible. to produce a 7 molecular weight, crystalline polymers by using as the catalyst for the polymerizationhydrogen fluoride or a fluoride which is readily hydrolyzed to give hydrogen fluoride in combination with a metal compound having the neral formula:

Where M is a metaliseilected from Groups II-A, Il-B, III-A, IV-A, IV-B, V-B, VI-B, and-VIII f the Periodic Patented Dec. 1, 1964 "ice I etc.

As stated above, the fluoride used is either hydrogen fluoride or a fluoride which is readily hydrolyzed to give.

hydrogen fluoride. In addition to hydrogen fluoride the fluorides, including oxy fluorides, of the elements, of Groups Ill-A, IVA, V-A, and VI-A of the Periodic Table can be used. Exemplary of these fluoride-s are aluminum fluoride, boron trifluoride, silicon tetrafluoride, stannic fluoride, phosphorus trifluoride, phosphorus oxyfiuoride, phosphorus pentafluoride, sulfur monofluoride, sulfur tetrafluoride, thionyl fluoride, etc.

The fluoride and the metalcompound can be premixed and used in the polymerization reaction or'they can be mixed in situ. Preferably they are mixed in an inert, anhydrous, liquid, organic diluent at a temperature of from about l00 C. to about 15 C., more preferably from about -80 C. to about 100 C., and then used as such alone or with an additional amount of the metal compound for the polymerization. For example, excellent results have been obtained when a small quantity of metal alkoxide is first added to the vinyl ether to be polymerized whereby any traces of impurities such as water,

Table (Lange, Handbook of Chemistry, 8th ed., pages 56-57, published 1952), R is a hydrocarbon radical, such as alkyl, alkenyl, cycloalkyl,'cycloalkenyl, aryl, aralkyl, etc., R is hydrogemalkoxide, or an alkoxide derivative such as ajcetylacetonate, the sum of x and y is equal to n, the valence of the metal, x can be 0 to n and y can be 0 to 11 when R isalkoxide and 0 to 11-1 when R is hydrogen. When R is acetylacetonat'e a chelate may be formed. The polyethers so produced are high molecular weight, highly crystalline polymers that are capable of being formed into strong, orientable fibers and films.

Just what the catalyst species is when a vinyl ether is polymerized with one of the specified fluorides used in combination with one of the specified metal compounds is not known. Nonetheless, there is obtained a greatly improved result over that obtained when the metal come pound is omitted.

Any metal compound of the abovespecified metals 'that has the above formula can be combined with a fluoride to produce the catalyst used in accordance with the invention. Exemplary of these metal compoundsare organometallic compounds wherein there are attached to the metal only hydrogen or hydrocarbon radicals, as, for example, magnesium or zinc dihydrocarbons, aluminum trihydrocarbons, aluminum" dihyclrocarbon hy-' drides, etc., the corresponding gallium and indium com-- Another group of metal' pounds, tin tetraalkyls, etc. compounds are themetal alkoxides and their derivatives, as, for example, aluminum methoxide, ethoxide, propoxide, isopropoxid'e, butoxide, etc; aluminum acetylacetonate; titanium alkoxides, vanadium alkoxides, ferric alkoxides, zirconium alkoxides, etc.; and the mixed alkyl metal alkoxides, as, for example, ethyl aluminum diisopropoxide, diethyl aluminum monoethoxide, diethyl acid, etc., are removed, and then the premixed catalyst combination is added. In some cases it is advantageous to age the catalyst combination either at the mixing temperature or at a higher temperature. Whether the catalyst combination shouldbe aged, and under what con ditions, will, of course, depend upon the specific combination being used.

The amount of the catalyst combination used for the.

polymerization of the vinyl ethers can vary from a minor catalytic amount to a large excess, but generally willbe an amount such that the amount of fluoride used in the catalyst mixture will be within the range of'from about 0.001 mole of catalyst per mole of monomer to about 0.05 mole of catalyst per mole of monomer. The mole ratio of the fluoride compound to the metal compound can also be varied over a wide range, but preferably will be from about 0.01:1'to about 10:1. In the case of the boron trifluoride and of hydrogen fluoride, this ratio will preferably be from about 0.01:1 to about 2:1.

Any vinyl'alkyl ether can be polymerized or copolymerized with the above-described catalyst combination in accordance with this invention, as, for example,

vinyl methyl ether, propenyl methyl ether, vinyl ethyl ether, propenly ethyl ether, vinyl propyl ether, propenyl propyl ether, vinyl isopropyl ether, vinyl n-butyl ether, vinyl. isobutyl ether, vinyl tert.-butyl ether, vinyl neopentyl ether, vinyl 2-chloroethyl ether, vinyl 2-methoxyethyl ether, vinyl trifluoroethyl ether, l-methoxybutadiene,

etch

The polymerization can .be carried out with or without a diluent, but for ease of operation, separation of the catalyst from the polymer, etc., it is generally carried out in an inert diluent. Any anhydrous liquid, organic diluent that is inert under the reaction conditions can be used, as, for example, aliphatic, cycloaliphatic, or aromatic hydrocarbons, chlorinated hydrocarbons, ethers, esters, etc. Exemplary of such diluents are hexane, heptane, cyclohexane, benzene, toluene, xylene, etc, or a mixture of such hydrocarbons, methylene chloride, chloroform, carbon tetrachloride, ethylene dichloride, chlorobenzene, diethyl ether, diisopropyl ether, ethyl acetate, etc. 1 The selection of the, temperature and pressure used for the polymerization process will depend upon the activity of (the specific catalyst being used, the diluent used, etc. In general, the polymerization will be carried out at a temperature within the range of from about .'100 C. to about 200 C., and preferably from about C. to about C. In the same way, While atmospheric '2 1.? pressure or a pressure of only a few pounds can be used, the polymerization can be carried out under a wide range of pressure, as, for example, from a partial vacuumv to about 1000 pounds, and preferably from about atmospheric to about 500 pounds pressure. Higher pressures A The polymerization was carried out in each case by charging a polymerization vessel filled with nitrogen with 10 parts of vinyl methyl ether, 50 to 65 parts of methylene chloride in Examples l-3 and 7 parts of n-heptane in Example 4, and a specified amount of metal alkoxide as can, of course, be used, but generally do not appreciably activator. After equilibrating the vessel and contents alter the course of the polymerization. at the reaction temperature, the catalyst mixure prepared When the polymerization is carried out as described as described above was added. The reaction mixture was above, the polymer is readily isolated from the solution then agitated at the reaction temperature for the specified or slurry of polymer and diluent by simply removing the 10 time, after which the catalyst was destroyed by adding diluent by evaporation, filtration, or other such means. 2 parts of a 1 M solution of ammonia in ethanol. To the The polymer can then be purified to remove the catalyst reaction mixture was then added two parts of a 1% soluresidues by washing with an alcoholic or aqueous solution tion of 4,4'-thiobis(6-tert-butyl-m-cresol) in ethanol as a of acid or base or by dissolving the polymer in a suitable stabilizer, and the diluents were removed under vacuum. solvent, filtering to remove the insoluble catalyst and The crude polymer was extracted several times with then separating the polymer from the so-purified solution. methanol to separate the methanol-insoluble, highly crys- Frequently it is desirable to add a stabilizer such as 4,4'- talline polymer from the methanol-soluble, amorphous or thiobis(6-tert.-butyl-m-cresol), di-tert.-bu tyl-p-cresol, etc., slightly crystalline polymer. to protect the polymer during storage or during use under In Table 1 'is set forth the fluoride compound and the adverse conditions. metal alkoxide used to prepare the catalyst in each ex- In many cases the polymers produced in accordance ample and the amount of each, the amount of activator with this invention are mixtures of highly crystalline added to the vinyl methyl ether before addition of the polymers with amorphous or slightly crystalline polymers. premixed catalyst, the reaction time and temperature, In order to obtain a high solvent resistance and high and the RSV of the highly crystalline polymer produced, tensile strength it is generally advisable to remove any along with the percent of the total polymer that was amorphous polymer which is present. Sometimes it is highly crystalline.

' T able 1 Premixed Catalyst Combination Crystalline Polymcr Isolated Additional Metal Reaction Time and Ex- Alkoxide Added to Parts Temperature ample Fluoride Molar Monomer Percent Compound Parts Metal Allroxide Parts Ratio Y RSV. of Total F to M 2 1 BF; 0.010 "rnoacsrrm 0013 1:03 TKO-103110 0.022 {,g: 8:: 2.10 12 2 BF; 0.015 lino-1031103.--. 0. 047 1.1 lino-roam); 0. 208 2218: 2. 73 a1 a HF 0.000 Al(OiCaH7)a 0.17 1=2.s A1(O-iC3H7)3. 0. 22s 2: 8:: 4.4 70 4 I-IF 0. 04a Tao-10mm 0. 92 1:15 Tao-103m 0. 28 22 8:: 7.0 43

1 Added in two equal portions-one at beginning and a second one hour later.

2 Molar ratio of fluoride compound to metal compound.

also advisable to remove slightly crystalline polymer. This is readily done by washing the polymer with a solvent which dissolves the slightly crystalline and amorphous product, but which does not dissolve the highly crystalline product.

The following examples will illustrate the process of polymerizing vinyl others in accordance with this invention to high molecular weight, highly crystalline polymers. The molecular weight of the polymersproduced in these examples is indicated by the Reduced Specific Viscosity (RSV) given for each. By the term Reduced Specific Viscosity is meant the 17Sp/C determined on an 0.1% solution (0.1 g. of the polymer per 100 ml. of solution) of the polymer in chloroform at 25 C. All parts and percentages are by weight unless otherwise indicated.

EXAMPLES 1-4 In each of these examplesthe catalyst used was prepared by mixing the fluoride compound with the metal compound prior to use in the polymerization system. In Examples 1 and 2 a solution of boron trifluoride etherate in a 50:50 ether-heptane diluent was mixed with a solution of the metal compound, and the mixture was shaken for one hour with glass heads at room temperature prior to use. In Examples 3 and 4 anhydrous liquid hydrogen fluoride was added to a solution of the metal compound in n-heptane, and the mixture was shaken at room temperature with glass beads for one hour in Example 3 prior to use, and in Example 4 for two hours, and then was allowed to stand at room temperature overnight prior to use.

EXAMPLE 5 The catalyst used in this example was prepared by mixing 0.08 part of hydrogen fluoride with 0.2 part of triisobutyl aluminum in 0.6 part of n-heptane and aging for several weeks at room temperature.

A polymerization vessel was filled with nitrogen and then charged with 10.2 parts of vinyl methyl ether, 17.0 parts of diethyl ether, and 0.4 part of triisobutyl aluminum in 1 part of n-heptane. Then the above-described premixed catalyst was added and the reaction agitated at 30 C. for 68 hours. At the end of this time the reaction was distilled under vacuum to remove any unreacted monomer and the catalyst destroyed by adding 4 parts of a 1 M solution of ammonia in ethanol. The catalyst was removed by extraction with 4 parts of 10% methanolic HCl. The polymer was then washed several times with anhydrous ethanol, once with 0.1% sodium hydroxide in methanol, once with methanol, and once with an 0.05% solution of 4,4-thiobis(6-tert.-butyl-m-cresol) in methanol. The methanol-insoluble polymer was then dried for 16 hours at a temperature of 50 C. under vacuum. The resulting crystalline poly(vinyl methyl ether) had an RSV of 16.

EXAMPLE 6 The catalyst used in this example was prepared by injecting 14.3 parts of 0.5 M diethyl magnesium in diethyl ether into a 500 ml. reaction vessel filled with gaseous hydrogen fluoride. The vigorousness of the ensuing reaction required the venting of the reaction vessel. After the reaction subsided the vessel was pressured with nitrogen and agitated for one hour. An amount of diethyl ether suficient to restore the initial volume of diethyl ether was added and the catalyst aged for 20 hours at room temperature. Analysis showed the molar ratio of fluorine to magnesium to be 0.57: 1. r

A polymerization vessel was filled with nitrogen and charged with 2.5 parts of vinyl methyl ether and 7.3 parts of n-heptane. Then a 1.4 part aliquot of the above-described premixed catalyst was added and the reaction agitated at 30 C. for 43 hours. The crystalline polymer was extracted from the resulting slurry as described in Example 5. The resulting crystalline poly(vinyl methyl ether) amounted to a 21% conversion and had an RSV of 0.8.

What I claim and desire to protect by Letters Patent is:

1. The process of polymerizing vinyl alkyl ethers which comprises contacting at least one of said ethers with a catalyst formed by contacting hydrogen .iluoride with a metal compound having the formula where M is a metal selected from the group consisting of titanium, aluminum, magnesium, zinc, gallium, indium, tin, vanadium, iron, and zirconium, R is an alkyl hydrocarbon radical, R is a radical selected from the group consisting of hydrogen and alkoxide radicals, the sum of x and y is equal to n, the valence of said metal, at is zero to .n, and y is zero to n when R is an alkoxide and zero to n-l when R is hydrogen.

2. The process of claim 1 wherein the vinyl alkyl ether is vinyl methyl ether.

3. The process of claim 2 wherein the catalyst is that formed by mixing hydrogen fluoride with an aluminum alkoxide.

4. The process of claim 2 wherein the eat-alystis that formed by mixing hydrogen fluoride with a titanium alkoxide.

5. The process of claim 2 wherein the catalyst is that formed by mixing hydrogen fluoride with a trialkyl aluminum.

6. The process of claim 2 wherein the catalyst is that formed by mixing hydrogen fluoride with a dialkyl magnesium.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Topchiev et al., CA46: 2477a (1952). 

1. THE PROCESS OF POLYMERIZING VINYL ALKYL ESTERS WHICH COMPRISES CONTACTING AT LEAST ONE OF SAID ETHERS WITH A CATALYST FORMED BY CONTACTING HYDROGEN FLUORIDE WITH A METAL COMPOUND HAVING THE FORMULA 